High-output, transparent, stretchable triboelectric nanogenerator based on carbon nanotube thin film toward wearable energy harvesters

Abstract

Self-powered electronics can improve wearable health monitoring systems. Triboelectric generation, a type of energy harvesting technology, is a promising candidate as power source for wearable devices by generating electricity from body motion. For wearable energy harvesters, stretching is required for adaptation to dynamic three-dimensional body motions, and sufficient output power should be delivered for driving electronic devices. However, the currently demonstrated output power remains insufficient for using stretchable triboelectric generation in practice. We propose high-output (8 W/m2), stretchable triboelectric generators based on transparent carbon nanotube thin films. We realize high output by the surface treatment with fluorine plasma as well as stretchability by scalable and cost-effective spray coated carbon nanotube thin films. The carbon nanotube films also provide excellent scalability, optical transparency (95% transmittance), and durability under large deformations of tensile strain up to 80%. We also demonstrate applications to self-powered optical wireless communication sheets and gloves, where blue light emitting diodes are embedded in the triboelectric nanogenerator sheet and wired using stretchable carbon nanotube films. Our stretchable energy harvesting sheets can contribute to solve major problems in wearable electronics (i.e., power source limitations) at low cost.